1. Technical Field
The present invention relates to a contact switch structure and an electromagnetic relay provided with the contact switch structure.
2. Related Art
Conventionally, there is well known an electromagnetic relay, in which an excitation coil disposed around a fixed iron core is excited or demagnetized to attract or separate an armature to and from the fixed iron core, a movable touch piece attached to the armature is operated to open and close a movable contact provided in the movable touch piece with respect to a fixed contact disposed in an opposite position (for example, see Japanese Utility Model Publication Laid-Open No. 3-88246).
In the electromagnetic relay, in forming components such as the armature and the excitation coil, flash and burrs are generated or micro chips adheres to the components, and the flash, burrs and micro chips may remain as floating fine particles (diameter of about 20 μm). When the fine particle adheres to a surface of the contact, a contact resistance of the contact may be increased, or faulty electrical continuity may be generated in some cases. Therefore, after the flash and burrs are removed from each component or the component is cleaned, the further cleaning is also performed after assembly to prevent the generation of the fine particle, thereby enhancing contact reliability of the contact.
However, the generation of the fine particle cannot completely be prevented by the cleaning. Therefore, when the contact is opened from a closed state, air flows between the contacts from the surroundings, and possibly the flying fine particle adheres to the surface of the contact.
There is also proposed a method for increasing the number of poles of the contact (the contact is switched in multi-pole-to-multi-pole manner) in order to enhance the contact reliability of the contact. However, unfortunately an occupied space of the contact switch mechanism is increased, thus causing enlargement of the device.